The present invention relates to a splitter bypass system and method for monitoring, testing and maintaining copper loops and lines. More particularly, the present invention is directed to a system and method for actuating bypass functions to bypass a splitter or portions thereof for enabling pure metallic access to the loop, digital equipment, voice equipment, and/or test equipment. Switching devices are implemented in the present invention to bypass a low pass filter and/or a high pass filter in the splitter.
In the telecommunications industry, Plain Old Telephone Service (POTS) or voice services are ubiquitous. As is well known, POTS is analog in nature and is implemented over copper loops. Class 5 switches generally provide this type of service and lines or copper loops are used to connect the. Class 5 switch to the customer premise.
FIG. 1A illustrates a conventional system implementing POTS. The system includes a central office (CO) having a voice switch such as a Class 5 switch 2 connected to a telephone 4 in a customer premise. As known, the Class 5 switch 2 is connected to the telephone 4 via a local loop 6.
POTS typically requires a battery voltage on the copper loop 6. The battery voltage is used for signaling, and this type of loop is known as a xe2x80x9cwetxe2x80x9d loop. For detecting faults/problems or for routine testing, the copper loop 6 connecting the Class 5 switch 2 to the customer premise is tested using test equipment 8 having pure metallic access to the loop 6, as illustrated in FIG. 1B. Pure metallic test access allows accurate testing on the copper loop 6 and is implemented through the Class 5 switch 2.
Recently, the need for increased bandwidth has resulted in the emergence of digital services on the existing copper loops. These emerging digital service use non-voice frequency bandwidth. This has placed increased requirements on the copper loops to provide the digital services. As can be expected, some of the loop design rules used to deploy voice only services are no longer valid when digital services are added. Many of these digital services have been provided on xe2x80x9cdryxe2x80x9d copper, loops (i.e., loops without battery voltage), providing a data only circuit.
In 1999, the Federal Communications Commission (FCC) adopted rules to promote competition between local telephone companies and providers of high speed data services by directing the local telephone companies to share their telephone lines with such providers. With these rules, many companies can deploy new technologies on a faster, more cost-effective basis, thereby allowing residential and business customers to access broadband and POTS services from a choice of different providers.
Digital Subscriber Line or xDSL is one of the most promising new technologies for delivering superior service and higher speed connections over existing infrastructure. In addition, the growing demand for faster, more reliable Internet access has increased the demand for technologies that deliver higher speed connections over existing infrastructure. As known, different competing forms of digital subscriber line technologies are collectively designated as xDSL technologies with the xe2x80x9cxxe2x80x9d representing various one or more letter combinations, which are used in front of the xe2x80x9cDSLxe2x80x9d acronym to designate the type of technology being used. Some of the more prevalent xDSL technologies include HDSL, ADSL, SDSL, RADSL, VADSL, and VDSL. xDSL uses the existing copper loop that is traditionally used for conventional telephony to deliver data at high bandwidth.
Currently, the transmission rates for xDSL technologies are dependent on factors such as the distance between the central office and a particular customer, etc. Also, xDSL uses packet switching technology that operates independently of the voice telephone system, allowing telephone companies to provide Internet service and not lock up circuits for telephone calls. The copper loop can carry both voice and data signals simultaneously, in both directions, allowing the customer to log onto the. Internet and make a telephone call at the same time. Thus, it is easy to understand why xDSL is becoming the preferred system and method for sending/receiving analog and digital data/signals in the telecommunications industry.
The FCC line sharing ruling, along with the need to maximize the utilization of copper pairs, has brought about larger deployment of both voice and digital (data) services on the same copper loop. This has introduced the concept of a splitter in the local loop environment. The function of the splitter is to segregate the low frequency (voice) and high frequency (data) to the appropriate equipment. These splitters allow the voice equipment (e.g., Class 5 switches) and digital equipment (generally referred to as Digital Subscriber Loop Access Multiplexers or DSLAMs) to provide service simultaneously to a single subscriber.
FIG. 2 illustrates a simplified diagram of a conventional system implementing both voice and digital services. In the conventional system, the central office (CO) is connected to the customer""s telephone 4 and a computing device 10 or similar unit at the customer""s premise (home, office, etc.) using the copper loop 6. In the CO, the Class 5 switch 2 and a DSLAM 12 are connected to a CO splitter 20. As known, the Class 5 switch 2 includes circuitry for providing POTS (voice) service and the DSLAM 12 includes circuitry for providing digital service to the customer.
In greater detail, the CO splitter 20 is used to isolate the voice service from the digital service, or stated alternatively, to segregate low frequency (e.g., voice) and high frequency (e.g., data) to the appropriate equipment. The isolation generated by the CO splitter 20 is important for minimizing interference between the two types of services. The CO splitter 20 separates voice and data band signals received from the copper loop 6 and provides the respective signals to the Class 5 switch 2 and the DSLAM 12. The CO splitter 20 also combines the voice and data band signals received from the Class 5 switch 2 and the DSLAM 12 and provides the combined signals to the copper loop 6. The CO splitter 20 allows the voice equipment (Class 5 switch 2) and the digital equipment (DSLAM 12) to provide service simultaneously to a single subscriber.
The CO splitter 20 includes a low pass filter (LPF) 22 connected to the Class 5 switch 2 and a high pass filter (HPF) 24 connected to the DSLAM 12. The LPF 22 filters out higher band digital signals and prevents such signals from interfering with the Class 5 switch 2. Likewise, the HPF 24 filters out low band voice signals and prevents such signals from interfering with the DSLAM 12. In other words, the high frequency signals generated by the DSLAM 12 will not interfere with the Class 5 switch 2 because of the presence of the LPF 22, and the low frequency signals generated by the Class 5 switch 2 will not interfere with the DSLAM 12 because of the presence of the HPF 24.
A second remote (RT) splitter 30 having a LPF 32 and HPF 34 can be optionally installed at the customer""s premise based on the type of xDSL service. The LPF 32 is connected to the telephone 4 for filtering out high band signals, while the HPF 34 is connected to the computing device 10 for filtering out low band signals.
Again, FIG. 2 illustrates an overlay configuration where digital services are added on top of the existing voice services. As a result of this configuration, complexity and problems result in the deployment and testing of the system. As described above, testing from the voice equipment is performed with metallic access to the loop 6. With the introduction of the CO splitter 20, pure metallic access is lost. Access to the loop 6 is through the LPF 22, and the voice equipment is no longer the last element in the circuit looking out from the central office. In other words, the CO splitter 20 is now the last central office element, which is connected to both voice and digital equipment.
Additional problems arise between the DSLAM 12 and the CO splitter 20 and between the Class 5 switch 2 and the CO splitter 20. For example, there, is no provision for testing and isolation of problems in this configuration.
In more detail, introducing the CO splitter 20 in the system has the following testing disadvantages: (1) true or pure metallic access to the copper loop 6 is no longer available (see (A) in the FIG. 2), which limits the testing to low frequency testing through the LPF 22; (2) there is no pure access to the metallic connection between the Class 5 switch 2 and the CO splitter 20 (see (B) in the FIG. 2) to isolate wiring or other problems; (3) there is no pure access to the metallic connection between the DSLAM 12 and the CO splitter 20 (see (C) in the FIG. 2) to isolate wiring or other problems; and (4) there is no pure metallic testing capability from the DSLAM 12.
Deployment of digital services introduces various new requirements on the copper loop that are contrary to the design rules for voice only services. Loop qualification and testing become more important in this environment. As xDSL services are more widely deployed through splitters, testing capabilities become critical to ensure widespread deployment. The present invention is intended to overcome these problems of the prior art.
In view of the above-described problems of the prior art, it is an object of the present invention to provide a splitter bypass system and method.
It is another object of the present invention to provide a system and method for implementing a splitter bypass function in the existing infrastructure for improved monitoring, testing and maintenance.
It is yet another object of the present invention to provide a splitter bypass system and method for accessing the copper loop for monitoring, testing and maintenance with minimal interference and disturbance to the existing POTS services on the loop.
It is a further object of the present invention to provide a system and method for providing a reliable and effective manner for monitoring, testing and maintaining a copper loop in the voice and digital environments.
These and other objects of the present invention are obtained by providing a splitter bypass function that can be used with a conventional splitter in the current voice and digital system. The splitter bypass function is used for monitoring, testing and maintaining a copper loop. The splitter bypass operation includes the steps of selecting a copper loop or portions thereof for testing. Switching devices are introduced to bypass a low pass filter and/or a high pass filter in the splitter.